Originally Posted by
Dantheman
ZZZ, I'd be very cautious about the sleep data. These devices do not directly measure sleep in any way. They extrapolate sleep states from HR, HRV, and accelerometer data and the accuracy of the number the algorithm spits out is questionable. We are also very susceptible to induced belief effects from the sleep data trackers give us. There have been some very interesting studies where researchers provided subjects with hacked trackers that allowed them to manipulate the data; subjects sometimes got the real data and sometimes they got a fake score that was the opposite how well or not they actually slept. Subjects' self-reported mood states and objective performance on cognitive tests correlated far more closely with the number displayed on the device than their actual sleep score.